Oxygen consumption and ventilation of dogs during passive and active exercise

A comparison was made between the influence of passive and active exercise on the energy metabolism (EM) and respiratory parameters (RP) of dogs: respiratory minute volume and ventilatory equivalent for O2. Passive exercise was performed in 24 dogs, anesthetized with pentobarbital sodium and morphine or ketamine hydrochloride and pentobarbital sodium, by moving the four limbs at constant frequencies of 25, 45, or 80 movements/min before and after curarization. Active exercise was induced in 35 animals by electric stimulation of the quadriceps and triceps muscles or of the distal ends of femoral and radial nerves at the same frequencies previously indicated. Values obtained for EM and RP during passive exercise were not significantly different from those obtained during resting conditions; active exercise caused a significant increase which was directly proportional to the frequencies of limb movement. Our results indicate that passive muscle movement induces no alteration in O2 consumption and the possible relfexes generated in these experimental conditions were not apparently important on ventilatory control. In active movements, over the range of the frequencies studied, there is a proportional increase in O2 consumption followed by a corresponding increase in ventilation.